As of 13 years ago there were about 1.3 billion cattle worldwide. So humans outnumber them around 6:1. So humans would be cheaper based on availability.
However the average cattle (all breeds, both genders) weighs 753kg, whereas an average person is around 62kg (worldwide average).
That makes the average cow 12 times as massive as the average human. And cows have quite a high meat:bone:organ ratio.
So, there's some 980+ billion kilos of cattle, compared to 460+ billion kg of human on the planet.
So just by population alone cattle should be cheaper per pound than humans, let alone the cost of rearing a human to maturity, which takes 18 years of feeding and sheltering.
And human food is more expensive than grass for cattle.
If humans were raised and slaughtered like cattle, we could probably get away with feeding them some sort of soylent to keep down costs. the 18 years to maturity does make for a bit of a problem price-wise, but after the process has been going long enough for the new batch of humans to replace the old that can probably be taken out of account
Poll